Structural characterization, anti-tumor and immunomodulatory activity of intracellular polysaccharide from Armillaria luteo-virens

Polysaccharides of Floccularia luteovirens regulate intestinal immune response, and oxidative stress activity through MAPK/Nrf2/Keap1 signaling pathway in immunosuppressive mice

This study explores the novel immunomodulatory effects of polysaccharides from the rare Floccularia luteovirens, a fungus with significant potential yet unexplored bioactive components, traditionally used in Tibetan medicine. This study employs a wide array of analytical techniques, including HPGPC, HPLC, western blotting, ELISA, and 16S rRNA gene sequencing, to comprehensively investigate FLP1's effects. The main structure of FLP1 was characterized by IF-TR and NMR spectrometry. The structural backbone of FLP1 was →3,6)-β-D-Glcp-(1 → and →2,3)-α-D-Manp-(1→. After immunosuppressed mice treated with FLP1, the findings demonstrated that FLP1 stimulated the production of secretory sIgA and secretion of cytokines (IL-4, TNF-α, and IFN-γ) in the intestine of Cy-treated mice, resulting in the activation of the MAPK pathway. Additionally, FLP1 protected oxidative stress by triggering Nrf2/Keap1 pathways and antioxidation enzymes (SOD, MDA, T-AOC, CAT, and GSH-Px). It also enhanced the intestinal barrier function by regulating the villous height ratio and expression of tight-junction protein. Furthermore, FLP1 remarkably reversed the gut microbiota dysbiosis in immunosuppressed mice by increasing the abundance of Oscilliospiraceae, and Lachnospiraceae, and altered the fecal metabolites by increasing LysoPE (0:0/18:0); 0:0/16:0; 18:1(11Z)/0:0, LysoPG (16:0/0:0), LysoPG 18:1 (2n) PE (14:0/20:1), echinenone, 2-(2-Nitroimidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl) acetamide, and suberic acid which is closely related to the immunity function. These results suggested that FLP1 may regulate the intestinal immune response by modulating the gut microbiota and fecal metabolites in immunosuppressed mice thereby activating the immune system.

Effect of H2O2-VC degradation on structural characteristics and immunomodulatory activity of larch arabinogalactan

The arabinogalactan in the representative softwood biomass of larch was degraded using an environmentally friendly hydrogen peroxide and vitamin C (H2O2-VC) system to improve its immunomodulatory activity. Through the H2O2-VC degradation mechanism, hydroxyl radicals are generated, which then target the hydrogen atoms within polysaccharides, resulting in the breaking of glycosidic bonds. Given the impact of oxidative degradation on polysaccharides, we identified three specific arabinogalactan degradation products distinguished by their arabinosyl side chain compositions. The primary structures of the degradation products were investigated using Fourier-transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. Congo red staining showed that the degradation products were absent in the triple-helix structure. The results of the in vitro immunological experiments indicated that an appropriate reduction in the molar ratio of arabinose to galactose enhanced the immunostimulatory effects on RAW 264.7 cells. In addition, the immunostimulatory pathway mediated by arabinogalactan was explored by toll-like receptor 4 (TLR4) inhibitor (TAK-242) These findings provide novel insights into the understanding of the relationship between the structure of arabinogalactan and its biological activity.

Isolation, structural characterization and immunomodulatory activity on RAW264.7 cells of a novel exopolysaccharide of Dictyophora rubrovalvata

Fungal polysaccharides have been explored by many for both structural studies and biological activities, but few studies have been done on the extracellular polysaccharides of Dictyophora rubrovalvata, so a new exopolysaccharide was isolated from Dictyophora rubrovalvata and its structure and its immunological activity were investigated. The crude exopolysaccharide (EPS) was purified by DEAE52 cellulose and Sephadex G-200 to obtain a new acidic polysaccharide (DR-EPS). DR-EPS (2.66 × 103 kDa) was consisted mainly of mannose, glucose, galactose and glucuronic acid with a molar ratio of 1: 0.86: 0.20: 0.01. In addition, DR-EPS increased the phagocytic activity of RAW264.7 cells up to 2.67 times of the blank control group. DR-EPS improved intracellular nucleic acid and glycogen metabolism as observed by AO and PAS staining. DR-EPS(40 μg/mL) promoted NO production up to 30.66 μmol, enhanced acid phosphatase (ACP) and superoxide dismutase (SOD) activities, with activity maxima of 660 U/gprot and 96.27 U/mgprot, respectively, and DR-EPS (160 μg / mL) significantly increased the lysozyme content as 2.73 times of the control group. The good immunological activity of extracellular polysaccharides of Dictyophora rubrovalvata provides directions for the use of fermentation broths.

Structural Characterization and Anti-Inflammatory Activity of Polysaccharides from Tremella fuciformis on Monosodium Urate-Stimulated RAW264.7 Macrophages

The structural characteristics and anti-inflammatory activity of Tremella fuciformis polysaccharides (TFPs) were investigated. The study showed that TFPs were mainly composed of mannose, rhamnose, glucuronic acid, glucose, galactose, xylose, and fucose. TFPs significantly inhibited monosodium urate (MSU)-induced inflammation of RAW264.7 cells, as well as the secretion levels of TNF-α, IL-1β, and IL-18 cytokines. The concentrations of malondialdehyde and reactive oxygen species in RAW264.7 macrophages were reduced, but superoxide dismutase activity was increased. RNA-Seq technology was applied to explore the mechanisms of TFPs ameliorating MSU-induced inflammation of RAW264.7 macrophages. Results revealed that TFPs significantly reduce MSU-stimulated inflammatory damage in RAW 264.7 cells by inhibiting signaling pathways like the hypoxia inducible factor-1 (HIF-1) signaling pathway and erythroblastic oncogene B (ErbB) signaling pathway. This study provides a foundation for TFPs to be developed as novel anti-inflammatory drugs.